163 



Pennington (M. S.). Notas sobre un Caso de la Enfermedad llamada 

 " Ura,'' causada por la Larva de la Dermatobia cyamventris 

 Macq. I Notes on a case of " Ura", caused by tlie Larva of 

 D cyaniventns.]—Physis, Buenos Aires, iv, no. 18, 31st December 

 1919, pp. 577-578, 2 figs. [Received 19th July 1920.] 



A case is recorded of infestation by tbe larvae of Dermatobia cyam- 

 ventris, Macq., in an individual who had just returned to Buenos Aires 

 after a journey through Misiones and Alto Parana. These larvae had 

 punctured the skin in five places and embedded themselves m the, 

 flesh beneath, and were extracted with great difficulty. 



LiscHETTi (A. B.). Algunas Observaciones sobre la Morfologia de los 

 Huevos de Culex. [Some Observations on the Morphology of the 



Eggs of Culex.]— Physis, Buenos Aires, iv, no. 18, 31st December 

 I9T9, pp. 588-591. ' [Received 19th July 1920.] 



The " float " or hydrostatic apparatus that is appended to each egg 

 of Culex spp. and that enables the egg-mass to float like a raft on the 

 surface of water is described and illustrated. The joint action of all 

 the floats forming a raft gives such stability to the egg-mass that it is 

 almost impossible to submerge it. Even if this is done mechanically, 

 a small volume of air is retained between the base of the eggs and the 

 floats, which enables the whole mass to rise again to the surface 

 immediately the pressure is removed. 



LiscHETTi (A. B.). Un Verme del Genero Planaria, Enemigo natural 

 de las Larvas del Mosquito. [A Worm of the Genus Planaria as a 

 Natural Enemy of Mosquito Larvae.]— P/?ysw, Buenos Aires, iv, 

 no. 18, 31st December 1919, pp. 591-595. [Received 19th July 

 1920.] 



The fact that 30 larvae of Stegomyiafasciafa {Aedes calopm), placed 

 in a glass tank of water for breeding purposes, disappeared within two 

 days led to investigations to determine the reason. Thirty larvae of 

 Culex sp. introduced into the tank suffered the same fate, only a few 

 fragments being left. An examination of the flora and fauna of the 

 water was then made, and revealed among other things a number of 

 worms of the genus Planaria. The fact that young mosquito larvae 

 disappeared completely and that only the harder portions of older ones 

 were left, indicated that they were devoured by the Planaria, w^hich 

 was the only Uving organism in the water capable of such action. 

 Experiments were then made with 100 c.c. drinking w^ater into which 

 were placed 6 Planaria worms, and, in successive batches of about 10 

 to 20, 108 larvae of Culex spp. from 3 to 4 mm. long. A table shows 

 the length of time taken to dispose of the various batches of larvae ; 

 within 4 hours the 6 Planaria had devoured a total of 106 larvae, only 

 2 particularly large individuals escaping the general fate. The same 

 6 Planaria were immediately transferred to another vessel containing 

 200 Culex larvae of 4 to 5 mm. length, which they immediately attacked 

 and continued devouring with short intervals of rest. By midnight 

 many larvae were dead or dying and by 8 a.m. next day all had either 

 disappeared or were chnging to the bottom or sides of the receptacle. 



(70'J) ^^ 



